title: Caregiving, mortality, and mobility decline: the Health, Aging, and Body Composition (Health ABC) Study.
abstract: BACKGROUND
  Although caregivers report more stress than noncaregivers, few studies have found greater health decline in older caregivers. We hypothesized that caregivers may be more physically active than noncaregivers, which may protect them from health decline.
  
  
  METHODS
  The sample included 3075 healthy adults from the Health, Aging, and Body Composition (Health ABC) Study. They were aged 70 to 79 years in April 1997 to June 1998 and resided in Memphis, Tennessee, or Pittsburgh, Pennsylvania. Caregivers (680 [22.1%]) were participants who provided regular care or assistance for a child or a disabled or sick adult. Outcomes included all-cause mortality and incident mobility limitation (defined as difficulty walking one-quarter mile or climbing 10 steps on 2 consecutive semiannual contacts) during 8 years. Total physical activity included daily routine, exercise, and caregiving activity.
  
  
  RESULTS
  Overall, 20.6% of caregivers died and 50.9% developed mobility limitations vs 22.0% and 48.9% of noncaregivers, respectively. Associations differed by race and sex. Mortality and mobility limitation rates were 1.5 times higher in white caregivers (eg, among white female caregivers, adjusted hazard ratio for mortality, 1.6; 95% confidence interval, 1.0-2.5) but not for black female caregivers vs noncaregivers (adjusted hazard ratio for mortality, 0.9; 95% confidence interval, 0.5-1.4). Physical activity mediated these associations in most race-sex groups. High-intensity caregivers (ie, caregiving > or =24 hours per week) had elevated rates of decline when adjusted for physical activity but lower rates when not adjusted for activity.
  
  
  CONCLUSIONS
  Older white caregivers have poorer health outcomes than black female caregivers. Physical activity appears to mask the adverse effects of high-intensity caregiving in most race-sex groups.
authors.affiliation: Department of Epidemiology, Boston University School of Public Health, Boston, MA 02118, USA. lfredman@bu.edu
authors.forename: Lisa
authors.initials: L
authors.lastname: Fredman
authors.forename: Jane A
authors.initials: JA
authors.lastname: Cauley
authors.forename: Suzanne
authors.initials: S
authors.lastname: Satterfield
authors.forename: Eleanor
authors.initials: E
authors.lastname: Simonsick
authors.forename: S Melinda
authors.initials: SM
authors.lastname: Spencer
authors.forename: Hilsa N
authors.initials: HN
authors.lastname: Ayonayon
authors.forename: Tamara B
authors.initials: TB
authors.lastname: Harris
mesh_terms: D001741:Black or African American; D000368:Aged; D017028:Caregivers / Q000706:statistics & numerical data*; D015444:Exercise; D005260:Female; D006801:Humans; D008297:Male; D051346:Mobility Limitation; D009026:Mortality / Q000208:ethnology; D010414:Pennsylvania / Q000453:epidemiology; D013714:Tennessee / Q000453:epidemiology; D044465:White People